RE: [PATCH 2/3] KVM: nVMX: Fix fail to get nested ack intr's vector during nested vmexit

Zhang, Yang Z
2014-07-17T05:15:44Z

Wanpeng Li wrote on 2014-07-17:
> WARNING: CPU: 9 PID: 7251 at arch/x86/kvm/vmx.c:8719
> nested_vmx_vmexit+0xa4/0x233 [kvm_intel]() Modules linked in: tun
> nfsv3 nfs_acl auth_rpcgss oid_registry nfsv4 dns_resolver nfs fscache
> lockd sunrpc pci_stub netconsole kvm_intel kvm bridge stp llc autofs4
> 8021q ipv6 uinput joydev microcode pcspkr igb i2c_algo_bit ehci_pci
> ehci_hcd e1000e ixgbe ptp pps_core hwmon mdio i2c_i801 i2c_core
> tpm_tis tpm ipmi_si ipmi_msghandler isci libsas scsi_transport_sas
> button dm_mirror dm_region_hash dm_log dm_mod
> CPU: 9 PID: 7251 Comm: qemu-system-x86 Tainted: G W
> 3.16.0-rc1 #2
> Hardware name: Intel Corporation S2600CP/S2600CP, BIOS
> RMLSDP.86I.00.29.D696.1311111329 11/11/2013 000000000000220f
> ffff880ffd107bf8 ffffffff81493563 000000000000220f
> 0000000000000000 ffff880ffd107c38 ffffffff8103f0eb ffff880ffd107c48
> ffffffffa059709a ffff881ffc9e0040 ffff8800b74b8000 00000000ffffffff
> Call Trace: [<ffffffff81493563>] dump_stack+0x49/0x5e
> [<ffffffff8103f0eb>]
> warn_slowpath_common+0x7c/0x96 [<ffffffffa059709a>] ?
> nested_vmx_vmexit+0xa4/0x233 [kvm_intel] [<ffffffff8103f11a>]
> warn_slowpath_null+0x15/0x17 [<ffffffffa059709a>]
> nested_vmx_vmexit+0xa4/0x233 [kvm_intel] [<ffffffffa0594295>] ?
> nested_vmx_exit_handled+0x6a/0x39e [kvm_intel] [<ffffffffa0537931>] ?
> kvm_apic_has_interrupt+0x80/0xd5 [kvm] [<ffffffffa05972ec>]
> vmx_check_nested_events+0xc3/0xd3 [kvm_intel] [<ffffffffa051ebe9>]
> inject_pending_event+0xd0/0x16e [kvm] [<ffffffffa051efa0>]
> vcpu_enter_guest+0x319/0x704 [kvm]
>
> After commit 77b0f5d (KVM: nVMX: Ack and write vector info to
> intr_info if L1 asks us to), "Acknowledge interrupt on exit" behavior
> can be emulated. Current logic will ask for intr vector if it is
> nested vmexit and VM_EXIT_ACK_INTR_ON_EXIT is set by L1. However, intr
> vector for posted intr can't be got by generic read pending interrupt
> vector and intack routine, there is a requirement to sync from pir to
> irr. This patch fix it by ask the intr vector after sync pir to irr.
>
> Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>

Reviewed-by: Yang Zhang <yang.z.zhang@intel.com>

> ---
> arch/x86/kvm/lapic.c | 1 +
> arch/x86/kvm/vmx.c | 3 +++
> 2 files changed, 4 insertions(+)
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index
> 0069118..b7d45dc 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -1637,6 +1637,7 @@ int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu)
> apic_clear_irr(vector, apic);
> return vector;
> }
> +EXPORT_SYMBOL_GPL(kvm_get_apic_interrupt);
>
> void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
> struct kvm_lapic_state *s)
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index
> 4ae5ad8..31f1479 100644 --- a/arch/x86/kvm/vmx.c +++
> b/arch/x86/kvm/vmx.c @@ -8697,6 +8697,9 @@ static void
> nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
> if ((exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
> && nested_exit_intr_ack_set(vcpu)) {
> int irq = kvm_cpu_get_interrupt(vcpu);
> +
> + if (irq < 0 && kvm_apic_vid_enabled(vcpu->kvm))
> + irq = kvm_get_apic_interrupt(vcpu);
> WARN_ON(irq < 0);
> vmcs12->vm_exit_intr_info = irq |
> INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR;

Best regards,
Yang